Darren,
Nikon has a long-established tradition of releasing a non-pro version of their pro camera within a year or two of the pro body's availability -- e.g., the Nikkormat after the F, the FG, FM2 and FE2 after the F3, the F801 after the F4, the F100 after the F5, the D100 after the D1x, and the D200 after the D2X. The pattern is clear -- if you can wait, you get most, sometimes even more, of the pro features for considerably less money in a lighter, more compact package.
What's unusual now is that the full-frame D700 is coming so close on the heels of the D3, but the realities of digital cameras are such that a two-year gap might as well be an eternity.
Nikon could have waited another year to launch the D700 to get more D3 sales, but in the meantime they'd have no 5D equivalent and if they had sat out the moderately affordable full-frame match much longer, they'd have lost the game to Canon.
Joe